Presentation is loading. Please wait.

Presentation is loading. Please wait.

4 Categorical Propositions

Published byJohan Santoso Modified over 5 years ago

Similar presentations

Presentation on theme: "4 Categorical Propositions"— Presentation transcript:

1 4 Categorical Propositions
4.5 Traditional Square of Opposition

2 Traditional Square of Opposition
Contrary A E T T Contra dictory Subalternation Subalternation Contra dictory F F I O Subcontrary Supposing one proposition is true (or false), you can tell the truth value of its opposite, and quite a bit more …

3 Traditional Square of Opposition
Contrary A E T T Contra dictory Subalternation Subalternation Contra dictory F F I O Subcontrary Contrary propositions (A and E propositions) cannot both be true, though both can be false (and at least one IS false)

4 Traditional Square of Opposition
Contrary A E T T Contra dictory Subalternation Subalternation Contra dictory F F I O Subcontrary Subcontrary propositions (I and O propositions) cannot both be false, though they can both be true (and at least one IS true)

5 Traditional Square of Opposition
Contrary A E T T Contra dictory Subalternation Subalternation Contra dictory F F I O Subcontrary Subalternation: truth flows downward, falsehood flows upward (if an I or O propositions is false, then so is the proposition above it)

6 Traditional Square of Opposition
Terminology for the traditional square: Undetermined truth value =df occurs if the truth value of a given proposition cannot be determined using another proposition, its truth value (truth or falsehood), and the rules of the square Illicit contrary =df inferring via the contrariety relation the truth value of an A or E proposition that is undetermined Illicit subcontrary =df inferring via the subcontrariety relation the truth value of an I or O proposition that is undetermined Illicit subalternation =df inferring any proposition (A E I or O) via a subalternation relation that is undetermined

7 Existential Fallacies
Existential fallacy in the traditional square =df using contrary, subcontrary, and subalternation with propositions about non-existent things. Existential fallacy in the Boolean square =df when our argument is invalid merely because a universal premise is interpreted as having existential import.

8 Conditional Validity When the validity of an argument depends on the existence of the subject matter. All redheads in this class are expelled students. Therefore, some redheads in this class are expelled students. Valid only if there are redheads in this class … and so ‘conditionally valid’.

Download ppt "4 Categorical Propositions"

Similar presentations

Test the validity of this argument: Some lawyers are judges. Some judges are politicians. Therefore, some lawyers are politicians. A. Valid B. Invalid.

Test the validity of this argument: Some lawyers are judges. Some judges are politicians. Therefore, some lawyers are politicians. A. Valid B. Invalid.
Rules of Inferences Section 1.5. Definitions Argument: is a sequence of propositions (premises) that end with a proposition called conclusion. Valid Argument:

Rules of Inferences Section 1.5. Definitions Argument: is a sequence of propositions (premises) that end with a proposition called conclusion. Valid Argument:
1 Valid and Invalid arguments. 2 Definition of Argument Sequence of statements: Statement 1; Statement 2; Therefore, Statement 3. Statements 1 and 2 are.

1 Valid and Invalid arguments. 2 Definition of Argument Sequence of statements: Statement 1; Statement 2; Therefore, Statement 3. Statements 1 and 2 are.
An overview Lecture prepared for MODULE-13 (Western Logic) BY- MINAKSHI PRAMANICK Guest Lecturer, Dept. Of Philosophy.

An overview Lecture prepared for MODULE-13 (Western Logic) BY- MINAKSHI PRAMANICK Guest Lecturer, Dept. Of Philosophy.
CPSC 121: Models of Computation Unit 6 Rewriting Predicate Logic Statements Based on slides by Patrice Belleville and Steve Wolfman.

CPSC 121: Models of Computation Unit 6 Rewriting Predicate Logic Statements Based on slides by Patrice Belleville and Steve Wolfman.
Deductive Arguments: Categorical Logic

Deductive Arguments: Categorical Logic
Use a truth table to determine the validity or invalidity of this argument. First, translate into standard form “Martin is not buying a new car, since.

Use a truth table to determine the validity or invalidity of this argument. First, translate into standard form “Martin is not buying a new car, since.
Today’s Topics Introduction to Predicate Logic Venn Diagrams Categorical Syllogisms Venn Diagram tests for validity Rule tests for validity.

Today’s Topics Introduction to Predicate Logic Venn Diagrams Categorical Syllogisms Venn Diagram tests for validity Rule tests for validity.
Critical Thinking Lecture 9 The Square of Opposition By David Kelsey.

Critical Thinking Lecture 9 The Square of Opposition By David Kelsey.
Philosophy 103 Linguistics 103 Yet, still, Even further More and yet more, etc., ad infinitum, Introductory Logic: Critical Thinking Dr. Robert Barnard.

Philosophy 103 Linguistics 103 Yet, still, Even further More and yet more, etc., ad infinitum, Introductory Logic: Critical Thinking Dr. Robert Barnard.
Proving the implications of the truth functional notions  How to prove claims that are the implications of the truth functional notions  Remember that.

Proving the implications of the truth functional notions  How to prove claims that are the implications of the truth functional notions  Remember that.
Syllogistic Logic 1. C Categorical Propositions 2. V Venn Diagram 3. The Square of Opposition: Tradition / Modern 4. C Conversion, Obversion, Contraposition.

Syllogistic Logic 1. C Categorical Propositions 2. V Venn Diagram 3. The Square of Opposition: Tradition / Modern 4. C Conversion, Obversion, Contraposition.
Copyright © Peter Cappello Logical Inferences Goals for propositional logic 1.Introduce notion of a valid argument & rules of inference. 2.Use inference.

Copyright © Peter Cappello Logical Inferences Goals for propositional logic 1.Introduce notion of a valid argument & rules of inference. 2.Use inference.
1.5 Rules of Inference.

1.5 Rules of Inference.
MATERI II PROPOSISI. 2 Tautology and Contradiction Definition A tautology is a statement form that is always true. A statement whose form is a tautology.

MATERI II PROPOSISI. 2 Tautology and Contradiction Definition A tautology is a statement form that is always true. A statement whose form is a tautology.
CATEGORICAL PROPOSITIONS, CHP. 8 DEDUCTIVE LOGIC VS INDUCTIVE LOGIC ONE CENTRAL PURPOSE: UNDERSTANDING CATEGORICAL SYLLOGISMS AS THE BUILDING BLOCKS OF.

CATEGORICAL PROPOSITIONS, CHP. 8 DEDUCTIVE LOGIC VS INDUCTIVE LOGIC ONE CENTRAL PURPOSE: UNDERSTANDING CATEGORICAL SYLLOGISMS AS THE BUILDING BLOCKS OF.
GLE 0701.5.5 Explore the concept of premises, including false premises. Intro to Logic.

GLE Explore the concept of premises, including false premises. Intro to Logic.
0 Validity & Invalidity (Exercises) December 23, 2005.

0 Validity & Invalidity (Exercises) December 23, 2005.
The Inverse Error Jeffrey Martinez Math 170 Dr. Lipika Deka 10/15/13.

The Inverse Error Jeffrey Martinez Math 170 Dr. Lipika Deka 10/15/13.
Question of the Day!  We shared a lot of examples of illogical arguments!  But how do you make a LOGICAL argument? What does your argument need? What.

Question of the Day!  We shared a lot of examples of illogical arguments!  But how do you make a LOGICAL argument? What does your argument need? What.

Similar presentations

Ads by Google